strnage behavoir

Question
Hi- I have a 7 year old pure breed fawn color Chihuahua. He is active and spry. A few days ago he began wierd behavior such as not being involved and yelping for no reason, tail down and has a nervous twitch. He does this during thunder storms for there hasnt been any. There has been no change in diet or surroundings, however my downstairs neighbor did get a new girl puppy (spayed)that he has not met yet. The dog did go to the vet and everything checks out fine. He does snap out of it, eats his meals and treats and drinks his water.  Every once in a while he then starts up again for no reason.  
What do you make of this?

Answer
Hi Michael...

I honestly don't know what to make of it with the small amount of information that you've provided to me. It's absolutely impossible to diagnose a dog over the internet and this doesn't sound like a behavioral problem to me or something caused by your neighbors having acquired a spayed dog.

When you say that "the dog" went to the vet and everything checks out fine, do you mean that YOUR dog went to the vet?  And what did they check that checked out fine?  Did they do blood work, did they do neurological testing or take any xrays of his back and neck area?

What is occurring at those times that he starts up again?  I know you said that it starts up for no apparent reason, but what has occurred prior to the "episodes"?  Did he eat 20 minutes before?  Did he pass stools that were really hard and difficult to pass?  I ask because there is a condition in Chihuahuas where they exhibit unusual behavior awhile after eating and it has to do with the liver.  Do you know what the elevations are for his liver enzymes?  Seizures can also present just exactly as you described.  People are of the mistaken impression that seizures are only when a dog falls over on its side and rolls it's eyes and obviously convulses - NOT so.

He does EXACTLY this when you have thunder storms?  EXACTLY???  

Get back to me with answers to the above questions if you desire.

Jo Ann